Before u get married,JPN need to advertise for X days notice of marriage at their branch. If no one object, then you can proceed. It make no sense to advertise wedding notice in a location where the couple don't live in. JPN refer to IC address to determine where a person is living.

If the couple is from 2 different state,JPN from each state need to put up their wedding notice. You get around it by changing IC address.

If you want to organise your ROM at somewhere nice instead of JPN office. You need to select a location,check which state it's in,check with JPN HQ of that state,put in request for out of JPN office ROM. Pay some money for MB to approve and an officer will come to site